Opamp front end examples

jaycee · 26th December 2006, 11:24 AM

Hi,

Just bored and pondering over power amps that use opamps in their front end instead of a discrete LTP. Anyone got any links to schematics of other amps like this?

So far, i've looked at the MF B1 and the Arcam DiVA A90 amplifier.

RSK · 26th December 2006, 12:05 PM

Try white noise audio. I have the MOS125 circuits and they sound good.

Cheers,

RSK.

latala · 26th December 2006, 12:20 PM

try also bgw /amcron/ phase linear /musical fidelity
thee are loads of them out there!
regards trev

ash_dac · 26th December 2006, 03:40 PM

Quote:

Originally posted by jaycee
Hi,

Just bored and pondering over power amps that use opamps in their front end instead of a discrete LTP. Anyone got any links to schematics of other amps like this?

So far, i've looked at the MF B1 and the Arcam DiVA A90 amplifier.

Rega Brio thread. But you posted on that thread

Rega Brio (one channel dead)

Lenin · 8th February 2007, 11:54 PM

Mmmmm.....

Look at the MF schematics (particularly for the P170, P270, P370, P470). The DO use a LM318 op-amp front ends, but the internal long-tailed pair is disabled, allowing the use of an all discrete version.

Errrr... I guess that is kinda the exact reverse of what you are after (semi-discrete rather than op-amp only front end) but worth a look...

By the way, no-one on this forum has yet been able to work out how to utilise other opamps in that particular MF topology. (Much to my frustration........!)

AndrewT · 9th February 2007, 05:30 PM

Hi,
the British J.E.Sugden P128 uses 5534 as a times 2 gain stage at the front end. It is outside the global NFB.
Sugden P128

jcx · 10th February 2007, 12:59 AM

http://www.qscaudio.com/support/libr...ies/rmx850.pdf

ne5532 and floating ouput supplies

scott wurcer · 10th February 2007, 01:54 PM

The Sumo-9 used two LF353's in the in-amp configuration. Kind of a cute circuit, and the patent's expired.

AKN · 10th February 2007, 09:42 PM

hi,

Lets not forget Jan Dupont and his "LYNX" poweramp.
http://www.audio-circuit.dk/LYNX_main.html
Further developed into PA-34 II
http://www.delta-audio.com/PA-34A.htm

sixtek · 10th February 2007, 10:18 PM

Quote:

Originally posted by 4fun
hi,

Lets not forget Jan Dupont and his "LYNX" poweramp.
http://www.audio-circuit.dk/LYNX_main.html
Further developed into PA-34 II
http://www.delta-audio.com/PA-34A.htm

Hmmm... These are reminding me the Phase Linear model 300.
The same circuit with modern devices.

26th December 2006, 11:24 AM	#1
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	Opamp front end examples Hi, Just bored and pondering over power amps that use opamps in their front end instead of a discrete LTP. Anyone got any links to schematics of other amps like this? So far, i've looked at the MF B1 and the Arcam DiVA A90 amplifier.

26th December 2006, 12:05 PM	#2
RSK diyAudio Member Join Date: Nov 2004 Location: K.L.	OPA134 front end Try white noise audio. I have the MOS125 circuits and they sound good. Cheers, RSK.

8th February 2007, 11:54 PM	#5
Lenin diyAudio Member Join Date: Feb 2002 Location: London	Musical Fidelity Worth a look... Mmmmm..... Look at the MF schematics (particularly for the P170, P270, P370, P470). The DO use a LM318 op-amp front ends, but the internal long-tailed pair is disabled, allowing the use of an all discrete version. Errrr... I guess that is kinda the exact reverse of what you are after (semi-discrete rather than op-amp only front end) but worth a look... By the way, no-one on this forum has yet been able to work out how to utilise other opamps in that particular MF topology. (Much to my frustration........!)

9th February 2007, 05:30 PM	#6
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, the British J.E.Sugden P128 uses 5534 as a times 2 gain stage at the front end. It is outside the global NFB. Sugden P128 __________________ regards Andrew T.

10th February 2007, 01:54 PM	#8
scott wurcer diyAudio Member Join Date: Jan 2004 Location: cambridge ma	The Sumo-9 used two LF353's in the in-amp configuration. Kind of a cute circuit, and the patent's expired. __________________ 2012, our time is running out.


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

26th December 2006, 12:20 PM	#3
latala diyAudio Member Join Date: Feb 2006 Location: staffordshire	try also bgw /amcron/ phase linear /musical fidelity thee are loads of them out there! regards trev

10th February 2007, 12:59 AM	#7
jcx diyAudio Member Join Date: Feb 2003 Location: ..	http://www.qscaudio.com/support/libr...ies/rmx850.pdf ne5532 and floating ouput supplies

10th February 2007, 09:42 PM	#9
AKN Enjoy good sound diyAudio Member Join Date: Aug 2005 Location: In the middle of Sweden	hi, Lets not forget Jan Dupont and his "LYNX" poweramp. http://www.audio-circuit.dk/LYNX_main.html Further developed into PA-34 II http://www.delta-audio.com/PA-34A.htm __________________ / Anders

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